This is the so-called Type Character. It is used as a short hand to declare constant values ββof a particular type. In your case, Sturns the value &HCinto Short(Int16).
Usually they are used in this way when you do not specify the type of the variable in the form As [type]:
Dim number = 56L 'This makes 'number' a variable of type Long.
Byte , , - a Short.
: (Visual Basic) | Microsoft